There are numerous applications in which a highly orderly winding of a filament on a bobbin is required. For instance, this is needed in order to permit the rapid unwinding of the filament from the bobbin. In order for the winding to be effected in an orderly manner it is required that the following conditions be fulfilled:
a) The filament wound onto the preceding layer is positioned in the space between adjacent windings;
b) The angular location of the filament at the transition from one layer to the next one is effected with high accuracy;
c) The number of step-back turns between the end of one layer and the beginning of the next layer is effected with high accuracy;
d) Cross-over points are positioned at predetermined locations;
e) An adhesive is applied to the wound layers to maintain fiber pack stability and to regulate the pay-out process.
The winding operation is conventionally effected using a winding machine comprising means for rotating the bobbin, means for supplying the wound filament from a supply reel at a predetermined tension, means for moving the fiber feed pulley parallel to the bobbin as winding proceeds and to reverse this movement as a new layer is wound, and means for applying an adhesive to the uppermost wound layer or to the filament at a location between the feed pulley and the bobbin.
One of the applications for such windings is a communication link between unmanned aircraft., or various types of missiles and glide bombs, and a launcher, using for this purpose an optical fiber or a metal wire.
The fibers to which the invention refers undergo extreme temperature changes, e.g., between -40.degree. C. and +55.degree. C., and must be suitably wound so as to be able to undergo payout at extreme temperatures.
The winding of optical fibers or thin wire onto a bobbin is an operation which, for practical purposes, must be carried out at high speed and requires a high level of automation, because the fiber is normally very long.
The bobbin shape is often slightly tapered to facilitate payout.